9p/xen: fix release of IRQ

Kernel logs indicate an IRQ was double-freed.

Pass correct device ID during IRQ release.

Fixes: 71ebd719 ("xen/9pfs: connect to the backend")
Signed-off-by: Alex Zenla <alex@edera.dev>
Signed-off-by: Alexander Merritt <alexander@edera.dev>
Signed-off-by: Ariadne Conill <ariadne@ariadne.space>
Reviewed-by: Juergen Gross <jgross@suse.com>
Message-ID: <20241121225100.5736-1-alexander@edera.dev>
[Dominique: remove confusing variable reset to 0]
Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>